Oral melanocytic nevi: a clinicopathologic study of 100 cases

Pigmented Lesions of the Oral Cavity

Pigmented lesions are a common finding in the oral cavity. Oral pigmented lesions may range from solitary to multiple, pinpoint to diffuse, and have a variety of clinical implications. Nearly all solitary pigmented lesions require a biopsy to rule out mucosal melanoma. Oral mucosal melanoma has a grim prognosis and early discovery is of utmost importance. Multiple pigmented lesions in the oral cavity may indicate a systemic condition about which the patient may not be aware. The presentation and management of these various lesions is the focus of this article.

PRAME immunohistochemistry is useful in differentiating oral melanomas from nevi and melanotic macules

BACKGROUND

Oral melanocytic neoplasms pose a diagnostic challenge to pathologists owing to their rarity relative to those in the skin. The utility of PRAME in distinguishing nevi from melanomas has been established in the skin, but limited information exists regarding its usefulness in the oral cavity.

METHODS

Thirty-five previously diagnosed pigmented oral lesions were retrospectively evaluated with PRAME. The lesions consisted of 16 oral nevi, 10 melanomas, and 10 melanotic macules.

RESULTS

Strong and diffuse nuclear PRAME staining was observed in all but one of the oral melanomas, which showed no staining. No nuclear PRAME staining was observed in any of the oral nevi or melanotic macules.

CONCLUSIONS

PRAME is a useful tool in the evaluation of oral melanocytic neoplasms. Our data indicate that PRAME is a highly specific but incompletely sensitive marker of oral melanoma. Larger studies could further illuminate the diagnostic value of PRAME in oral lesions.

Blue Nevus of the Hard Palate: The Importance of a Careful Examination in an Emergency Setting

Oral common blue nevus is an asymptomatic, benign, rare, pigmented lesion and sometimes clinically indistinguishable from other pigmented lesions such as the cellular blue nevus or early-stage malignant melanoma. Since it shows clinical similarities with a malignant lesion and with cellular blue nevus that can itself suffer malignant transformation, the decisive diagnosis is crucial for adequate treatment, follow-up, and prognosis. Diagnosis confirmation is given by histological analysis, the reason why most oral pigmented lesions are excised. The following case presents an asymptomatic oral pigmented lesion of the hard palate discovered during observation in an emergency setting due to an abscess of dental origin. The lesion was fully excised, and histological examination reported a “common blue nevus.” In this case, we intend to present a rare lesion of the oral cavity and the importance of performing a routine oral examination when given a chance as a preventive approach.

Large Plaque-type Blue Nevus with GNAQ Q209P Mutation, Involving Mammary Gland Tissue: Under-Recognized Mammary Condition as an Origin of Primary Mammary Melanocytic Tumors

ABSTRACT

Plaque-type blue nevus is a rare variant of blue nevi that was first described in 1954. This article presents clinical, macroscopic, histopathological, and genetic findings for a case of large plaque-type blue nevus expanding into the mammary gland tissue as well as the skin of the right breast. A 63-year-old woman presented with a congenital, large, blue-colored macule limited to the hypochondriac area of the right breast. A nodule 8 mm in diameter was also present in the mammary gland tissue. Magnetic resonance imaging was unable to detect diffuse melanin deposition in the mammary gland tissue, but pigmentation in the whole mammary parenchyma was observed in the cut surfaces of the mastectomy specimen. Histopathology revealed a sparse distribution of dendritic melanocytes in whole sections of the mammary fibrous tissue and partial sections of the dermis. The histopathological criteria for atypical cellular blue nevus were fulfilled for the mammary tumor. Nodal blue nevus was diagnosed in the sentinel lymph node. Sanger sequencing confirmed the GNAQ Q209P mutation, which was also identified in all 4 literature cases of plaque-type blue nevus, but rarely in conventional blue nevi and uveal melanoma. It should be noted that plaque-type blue nevus can expand into the mammary gland tissue, even if the pigmented lesion does not exist on the overlying breast skin. The mammary condition can be the origin of primary mammary melanocytic tumors. Mosaicism of the GNAQ Q209P mutation can be a characteristic genetic alteration to extensive blue nevi, including plaque-type blue nevus.

An extensive intraoral blue nevus in an elder patient

OBJECTIVE

To report a rare case of intraoral extensive blue nevus in an elder patient.

BACKGROUND

Oral blue nevi is a well-recognised skin melanocytic neoplasm that rarely occurs in the oral cavity and may mimic melanoma in the early stages.

METHODS

An incisional biopsy was performed, and the diagnosis was blue nevus.

CONCLUSION

Both the clinician and pathologist must be aware of such a presentation to diagnose and treat appropriately.

Pigmented Oral Lesions: A Multicenter Study

Objectives  The aim of this study was to determine the prevalence and clinical features of pigmented oral lesions from Thailand.

Materials and Methods  Biopsy records of the Department of Oral Pathology, Chulalongkorn University, Department of Oral Diagnosis, KhonKaen University, Department of Oral Biology and Oral Diagnostic Sciences, Chiangmai University, Department of Stomatology, Prince of Songkla University, and Rangsit University were reviewed for oral pigmented lesions diagnosed during 1999 to 2019. Demographic data were culled from the biopsy records. Ages of the patients were subdivided into 10-year intervals. Locations of the lesions were classified as gingiva, labial/buccal mucosa, palate, floor of the mouth, tongue, as well as the combination of sites. Data were analyzed by descriptive statistics using SPSS version 20.0.

Results  Of the 47,175 accessioned cases, 241 cases (0.51%) were diagnosed in the category of pigmented oral lesions. The age of the patients ranged from 1 month to 88 years with the mean ± standard deviation = 38.74 ± 20.96 years. Regarding gender, 172 patients (71.37%) with pigmented lesions were females, while 69 patients (28.63%) were males. The female-to-male ratio was 2.49:1. The majority of the pigmented lesions were encountered at the gingiva (29.88%) followed by labial/buccal mucosa (26.97%), palate (14.94%), lip (10.79%), alveolar mucosa (9.54%), and others (7.88%), respectively. The three most common pigmented oral lesions in the present study were nevus (39.83%), followed by melanotic macule (28.63%) and amalgam tattoo (17.43%), respectively.

Conclusions  The most common pigmented oral lesion in the present study is nevus. Demographic data of the patients in the present study are in accordance with previous studies with minor differences. Even though pigmented lesions of the oral cavity constitute a small portion of the oral pathology biopsies, accurate diagnosis is important since there is an overlap in clinical appearance of benign pigmented lesions and melanoma.

Bone morphogenetic protein induces bone invasion of melanoma by epithelial-mesenchymal transition via the Smad1/5 signaling pathway

Oral malignant melanoma, which frequently invades the hard palate or maxillary bone, is extremely rare and has a poor prognosis. Bone morphogenetic protein (BMP) is abundantly expressed in bone matrix and is highly expressed in malignant melanoma, inducing an aggressive phenotype. We examined the role of BMP signaling in the acquisition of an aggressive phenotype in melanoma cells in vitro and in vivo. In five cases, immunohistochemistry indicated the phosphorylation of Smad1/5 (p-Smad1/5) in the nuclei of melanoma cells. In the B16 mouse and A2058 human melanoma cell lines, BMP2, BMP4, or BMP7 induces morphological changes accompanied by the downregulation of E-cadherin, and the upregulation of N-cadherin and Snail, markers of epithelial-mesenchymal transition (EMT). BMP2 also stimulates cell invasion by increasing matrix metalloproteinase activity in B16 cells. These effects were canceled by the addition of LDN193189, a specific inhibitor of Smad1/5 signaling. In vivo, the injection of B16 cells expressing constitutively activated ALK3 enhanced zygoma destruction in comparison to empty B16 cells by increasing osteoclast numbers. These results suggest that the activation of BMP signaling induces EMT, thus driving the acquisition of an aggressive phenotype in malignant melanoma.

Differential diagnoses of solitary and multiple pigmented lesions of the oral mucosa: Evaluation of 905 specimens submitted to histopathological examination

BACKGROUND

The aim was to analyze the frequency, clinical and demographic features of solitary and multiple/diffuse oral pigmented lesions submitted to histopathological examination, and to summarize the features that guide the clinical differential diagnosis.

METHODS

Clinical and demographic data were retrieved from biopsy records and descriptive statistics were performed.

RESULTS

Nine hundred and five (0.51%) oral pigmented lesions were retrieved among 177 356 specimens, being 95.9% solitary and 4.1% multiple/diffuse lesions. Regardless the overlapping clinical presentation, age, site, association with amalgam restoration, and a nodular appearance may help in the clinical differential diagnosis of solitary oral pigmentations. Patient's habits, site, and systemic signs and symptoms are helpful in the clinical differential diagnosis of multiple/diffuse lesions.

CONCLUSIONS

Oral pigmented lesions are a rare diagnosis in oral pathology and solitary lesions are more commonly submitted to biopsy. Some key features help in the differential diagnosis, though biopsy can be warranted in doubtful cases.

Mucosal Melanoma: Pathological Evolution, Pathway Dependency and Targeted Therapy

Mucosal melanoma (MM) is a rare melanoma subtype that originates from melanocytes within sun-protected mucous membranes. Compared with cutaneous melanoma (CM), MM has worse prognosis and lacks effective treatment options. Moreover, the endogenous or exogenous risk factors that influence mucosal melanocyte transformation, as well as the identity of MM precursor lesions, are ambiguous. Consequently, there remains a lack of molecular markers that can be used for early diagnosis, and therefore better management, of MM. In this review, we first summarize the main functions of mucosal melanocytes. Then, using oral mucosal melanoma (OMM) as a model, we discuss the distinct pathologic stages from benign mucosal melanocytes to metastatic MM, mapping the possible evolutionary trajectories that correspond to MM initiation and progression. We highlight key areas of ambiguity during the genetic evolution of MM from its benign lesions, and the resolution of which could aid in the discovery of new biomarkers for MM detection and diagnosis. We outline the key pathways that are altered in MM, including the MAPK pathway, the PI3K/AKT pathway, cell cycle regulation, telomere maintenance, and the RNA maturation process, and discuss targeted therapy strategies for MM currently in use or under investigation.

Oral pigmented lesions: a retrospective analysis from Brazil

Background

Pigmented lesions are uncommon in the oral mucosa, and studies investigating the incidence and types of these lesions are desired to improve the diagnostic knowledge of clinicians. The aim of this study was to analyze the distribution of oral pigmented lesions in a Brazilian population.

Material and Methods

A retrospective descriptive cross-sectional study was performed. Oral pigmented lesions were retrieved from the files of two oral and maxillofacial pathology services from Brazil over a 45-year period (1974-2019). The clinical data and the diagnoses of each case were retrieved and included in a Microsoft Excel® database.

Results

From 77.074 lesions diagnosed in this period, 761 (0.99%) represented pigmented lesions of the oral mucosa, including 351 (46.1%) melanocytic and 410 (53.9%) non-melanocytic lesions, with a higher incidence in females (73.2%) between the fourth and seventh decades of life. Amalgam tattoo (53.6%) represented the most common lesion, followed by melanotic macule (18.3%) and racial pigmentation (10.8%). Other pigmented lesions included nevus (9.9%), post-inflammatory pigmentation (3%), melanoma (2.1%), melanoacanthoma (1.4%), smoker's melanosis (0.4%), drug-induced pigmentation (0.3%), and melanotic neuroectodermal tumor of infancy (0.1%). The buccal mucosa was the most commonly affected site (25.2%), followed by the alveolar ridge (14.5%), and gingiva (11.8%).

Conclusions

The current findings were similar to previous studies with minor differences due methodology and characteristics of the services from where lesions were retrieved. The knowledge of these data may contribute to a better understanding of oral pigmented lesions and assist clinicians to better recognize and manage them.

Key words:Pigmented lesions, pigmentation, melanin, amalgam, oral cavity.

Intraoral atypical lentiginous melanocytic lesion in a pediatric patient

We present a rare case of intraoral atypical lentiginous melanocytic lesion affecting a pediatric patient, in which the diagnosis of lentiginous junctional melanocytic nevus with cytologic atypia was favored. The main differential diagnosis is lentiginous melanoma, which is a slowly progressing lesion, affecting mainly older adults, and microscopically presenting lentiginous growth pattern of moderately atypical melanocytes, with focal nesting and pagetoid spread. It is strongly recommended that melanocytic lesions showing features of atypical lentiginous growth pattern should be treated with wide excision; however, the impact of these guidelines on pediatric patients needs to be better defined with the report of further cases.

Pigmented Lesions

Oral pigmented lesions have a wide range of clinical presentations, some of which correlate with cutaneous pigmented lesions. This article highlights these correlates and underscores important differences that can potentially have clinical impact. Moreover, given a nonspecific presentation of an oral pigmented lesion, the article provides a reference to aid clinicians with differential diagnoses based on clinical features. This article is an overview of pigmented lesions of the oral cavity, including localized reactive pigmented lesions, neoplastic pigmented lesions, and pigmented lesions as sequelae of a systemic disease.

Potential association between oral mucosal nevus and melanoma: A preliminary clinicopathologic study

OBJECTIVES

To assess potential association between oral nevi (ON) and nevus-associated melanoma (NAM), in which melanoma cells coexist with nevus cells.

METHODS

A total of 74 ON patients and 7 NAM patients were retrospectively reviewed. Comparative and regression analyses of clinical and histological data were performed between two groups.

RESULTS

The mean age of the patients with ON was 36.5 years compared with that of 54.7 years of the patients with NAM (p = .008). Gender ratio was female predominance for ON (1.64:1 ratio) and male predominance for NAM (6:1 ratio). The most common location of ON and NAM was the palate (31.1%) and gingiva (71.4%), respectively. Univariate regression analysis revealed that elderly male patients (≥60 years) with junctional ON located on the gingiva correlate with higher risk of melanoma. Multivariate analysis revealed that junctional type of ON was an independent factor (adjusted OR, 38.32; 95% CI, 3.20-458.64; p = .004) associated significantly with increased risk for melanoma.

CONCLUSIONS

The preliminary study for the first time elucidated the clinicopathologic features of a Chinese series of ON and evaluated the potential association between ON and NAM with a limited sample size. Further large multicenter studies are needed to confirm the findings.

Black and Brown Oro-facial Mucocutaneous Neoplasms

Black and brown-colored mucocutaneous lesions present a differential diagnostic challenge, with malignant melanoma being the primary clinical concern. The vast majority of pigmented lesions in the head and neck region are the result of benign, reactive factors such as post-inflammatory melanosis. However, it is not uncommon to discover a range of muco-cutaneous black and brown neoplasms in the oro-facial area. The majority of black/brown pigmented neoplasms are melanocytic in origin; these are neoplasms of neural crest derivation. Melanocytic nevi are a diverse group of benign neoplasms that are the result of specific oncogenic mutations. They are common on cutaneous surfaces but can manifest in mucosal sites. Currently, nevi are classified based on clinical and histological criteria. The most common cutaneous and oral mucosal nevus is the acquired melanocytic nevus; nevi do not pose an increased risk for the development of malignant melanoma. Emerging information on specific genetic differences supports the notion of biologically distinct nevi. This article will review the classic clinical and microscopic features of nevi commonly found in the head and neck region, and discuss emerging concepts in nevus pathogenesis and taxonomy. Melanoma is a malignant melanocytic neoplasm and is a result of cumulative genetic deregulation. The etiology of malignant melanoma (MM) is multifactorial and includes underlying genetic susceptibility, UV radiation, skin-type, and race. The majority of MM occurs on cutaneous surfaces and less commonly on mucosal and extra-cutaneous visceral organs. Regardless of location, MM exhibits clinical-pathological features that relate to horizontal or vertical tumor spread. Cutaneous and mucosal MM typically present as asymmetrical, irregularly bordered, large (> 0.5 cm), heterogeneous brown-black lesions with foci of erythema, atrophy or ulceration. As with melanocytic nevi, advances in melanomagenesis research have revealed primary oncogenic BRAF and NRAS mutations associated with cutaneous MM. Unlike their cutaneous counterparts, mucosal melanomas exhibit primary oncogenic alterations in c-KIT and other genes. This article will discuss the role of specific primary oncogenic and secondary/tertiary genetic defects in differential clinical presentation, anatomic distribution, future classification changes, and targeted therapy of melanoma. The clinical and microscopic features of mucosal melanomas and a summary of management guidelines will be discussed. Additionally, this article will cover the salient features of melanocytic neuroectodermal tumor of infancy, a neoplastic entity that can involve the oro-facial region, and the clinical-pathological features of selected, commonly occurring pigmented ectodermally-derived neoplasms that are often part of the clinical differential diagnosis of black-brown pigmented lesions.

Amalgam tattoo versus melanocytic neoplasm - Differential diagnosis of dark pigmented oral mucosa lesions using infrared spectroscopy

Background

Dark pigmented lesions of the oral mucosa can represent a major diagnostic challenge. A biopsy is usually required to determine the nature of such intraoral discolorations. This study investigates the potential use of infrared spectroscopy for differential diagnosis of amalgam tattoos versus benign or malignant melanocytic neoplasms.

Materials and methods

For this retrospective study, formalin-fixed paraffin-embedded tissue (FFPE) specimens of dark pigmented lesions concerning the oral mucosa or the lip were investigated using mid infrared spectroscopy. The samples were chosen from patients who had undergone a mucosal biopsy at the University Hospital Innsbruck (Austria) between the years 2000 and 2017. Principal component analysis was used for data exploration. Evaluation was based on the superimposition of the recorded spectra and the corresponding histologic slides.

Results

In total, 22 FFPE specimens were analyzed. Clear differences were found between amalgam and non-amalgam samples. A general weakening of the penetrating infrared radiation allowed for unspecific discrimination between these two classes. An overall accuracy in predicting the correct class of 95.24% was achieved.

Conclusion

Infrared spectroscopy appears to be a suitable technique to differentiate between amalgam tattoos and melanocytic lesions in FFPE samples. It could potentially be applied in vivo, too, serving as a non-invasive diagnostic tool for intraoral dark pigmented lesions.

Solitary pigmented lesions in oral mucosa in Latin American children: A case series

BACKGROUND

A variety of local and systemic processes caused exogenous and endogenous pigmentation of the oral mucosa. Solitary melanotic pigmentation is rare, hence the scarce number of studies in children and adolescents.

METHODS

Clinical and histopathologic features of 10 Latin American children with solitary pigmented lesions of the oral mucosa were reviewed.

RESULTS

The area most affected was the gingiva, followed by the palate. All lesions were flat and <1 cm in diameter. A brown color was observed in oral melanocytic macules and nevi. The exogenously pigmented lesion was bluish gray. Histopathology showed that the biopsied lesions corresponded to melanotic macules, junctional nevus, blue nevus, and exogenous pigmentation.

CONCLUSION

Solitary pigmented lesions on the oral mucosa of children, from melanin pigment or exogenous pigment, may have a similar clinical presentation, but melanotic lesions such as oral melanotic macules and nevi can be differentiated from one another only with histopathologic examination.

Palatal Melanoma: "The Silent Killer"

Primary melanoma of the oral cavity is extremely uncommon tumour consisting approximately 0.2 - 8.0% of all melanoma cases and 0.5% of all oral malignancies. It has an aggressive behaviour and poor prognosis, with 5 - year - survival rate between 5 - 20%. The initial symptoms are often unnoticed, which lead to late diagnosis and worsening of the prognosis. Because of its infrequent occurrence, there is no well - defined classification and therapeutic protocol, in contrast to melanomas of another side. Early diagnosis and treatment are essentially linked to survival rate. We present a case of palatal melanoma in a 76 - year - old female patient, as we want to emphasise the importance of the early detection and accurate diagnosis of melanoma of oral cavity, to its influence of the therapeutic outcome.

Longitudinal clinicopathologic data of the progression of oral mucosal melanoma-report of 2 cases and literature review

Oral mucosal melanoma (OMM) is notorious for having a poor prognosis. Recognition of the early features of OMM by both clinicians and pathologists can play an important role in improving survival. Therefore, the purpose of this report is to increase awareness of the early features of OMM, by presenting 2 cases with longitudinal clinical and histopathologic documentation showing progression of OMM from a deceptively bland premalignant (noninvasive) oral melanocytic lesion (POML). By analyzing the clinical and histopathologic features of POML in our cases, and those in the literature, we found that the concerning features are (1) clinically, a pigmented lesion violating the ABCDE criteria or showing multiple recurrences; and (2) histologically, a melanocytic proliferation, in either a lentiginous or pagetoid pattern with or without cellular atypia. Making a diagnosis of POML prospectively is often challenging. Increasing awareness of the clinical and histopathologic features and complete surgical excision of POML are emphasized.

[Pigmentations of the oral cavity]

Buccal mucosa color is explained by hemoglobin in the vessels and melanin in the epithelium. Abnormal presence of melanin pigments (hypermelaninosis, hypermelanocytosis), hematic pigments (hemoglobin, hemosiderin, iron) but also some exogenous circonstancies explain pigmented lesions (figure 1). These lesions could be localized (single lesions), multifocal (multiple lesions) or diffused. In case of a localized pigmentation with melanic appearance, melanoma must be systematically eliminated with a biopsy. In the case of a more diffused lesion, systemic disease must be evoked. A drug etiology is also possible. A blood pigment excess could be a vascular malformation (flat lesions) or a tumoral process (nodular or swollen lesions). In both cases, Kaposi's disease should be systematically eliminated. Pigmentations near dental restorations (amalgams, prosthetic crowns) could be explained by an exogenous factor but a biopsy should be performed in case of a doubt with melanoma.

Pigmented oral compound nevus of retromolar area - A rare case report

Solitary pigmented melanocytic intraoral lesions of the oral cavity are rare. Oral nevus is a congenital or acquired benign neoplasm. Oral compound nevus constitutes 5.9%-16.5% of all oral melanocytic nevi. The oral compound nevus is commonly seen on hard palate and buccal mucosa and rarely on other intraoral sites. The objective of this article is to present a rare case report of oral compound nevus in the retromolar pad region along with a review of literature. A 22 year old female reported with a solitary black pigmented papule at retromolar pad region which was surgically removed and microscopic investigation confirmed the diagnosis of oral compound nevus.